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Car cuts out when cold

This is a discussion on Car cuts out when cold within the General Help forums, part of the LSx Technical Help Section category; Yesterday on the way to work, I stopped at a light and the car down shifted after I was stopped, ...

  1. #1
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    Car cuts out when cold

    Yesterday on the way to work, I stopped at a light and the car down shifted after I was stopped, very jerky. Then a few minutes later I was coasting down a hill and hit the gas, nothing. I thought it stalled but kicked in a few seconds later, same thing every minute or so. I thought about any changes I had made and thought the MAF might have got oil on it from when I cleaned the K&N over the weekend, so I went mid morning to the parts store (now warmer outside) and got a can of MAF cleaner, cleaned the MAF wires and drove around an hour of so, it was fine. When I got home I really cleaned the MAF, drove it and all was good. Now this a.m. it was 24F out, same thing happens. No check engine light, car is at 1k RPM when it happens. Acts like it's bogging and down shifts funny. It also took it about 15 min to hit the 160F mark, but still did it after it was there. Not sure what the thermostat in the car is. It's a 2000 TA with 54K miles on it.
    Last edited by eteller; 11-29-2012 at 05:04 AM.

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    I also bought a little code reader yesterday but I'm going to return it for a better one that shows live data (thought that might be helpful for other stuff), so I did not check it for codes.

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    Spaz is My Mentor SMWS6TA's Avatar
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    any codes popped up? post them

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    Former Mopar Man 2002ssslp's Avatar
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    Quote Originally Posted by eteller View Post
    Yesterday on the way to work, I stopped at a light and the car down shifted after I was stopped, very jerky. Then a few minutes later I was coasting down a hill and hit the gas, nothing. I thought it stalled but kicked in a few seconds later, same thing every minute or so. I thought about any changes I had made and thought the MAF might have got oil on it from when I cleaned the K&N over the weekend, so I went mid morning to the parts store (now warmer outside) and got a can of MAF cleaner, cleaned the MAF wires and drove around an hour of so, it was fine. When I got home I really cleaned the MAF, drove it and all was good. Now this a.m. it was 24F out, same thing happens. No check engine light, car is at 1k RPM when it happens. Acts like it's bogging and down shifts funny. It also took it about 15 min to hit the 160F mark, but still did it after it was there. Not sure what the thermostat in the car is. It's a 2000 TA with 54K miles on it.
    Stock thermostat for your car is 195 deg.
    My ride is a 2002 Camaro SS SLP #3296 with 30k, LTH, 3" Y, CME, Frost tune, K&N, ported TB, Blackwing lid, Bellows, MSD, Denso Iridium, and 85mm MAF, Bilsteins, Eibach springs, SLP strut brace, Adj. Panhard, TA Girdle, UMI, Pro 5.0, Nitto NT555
    My wife has a 2004 GTO with the rare SAP, 18" wheels, K&N Cold Air System, MSD, Ported TB, Frost tune, Denso Iridium, Flowmaster cat-back, 3200 Yank, 75k

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    Moderator 35th-ANV-SS's Avatar
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    It might be a transmission issue.

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    If no codes are being set, wouldn't be a bad idea to hook up a scanner and check you engine temp (as reported to the PCM, not the dash gauge) and your open/closed loop operation. Could be a combination of things, including a stat that is stuck open.

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    Ok, plugged in the scan tool this afternoon, and got 10 codes, still no CEL.
    P0102 which I think might be the culprit
    P0135 bank 1 sensor 1 (twice on this code)
    P0405 car has no egr
    P0412 car has no air pump
    P048 air pump
    P0135 bank 1 sensor 1
    P0405
    P0412
    P0418

    At this point I'm thinking it's either the MAF an O2 sensor or vac leak. The car has long tube headers so their are no rear O2 sensors, not sure if the PO put eliminators on it or not. Going to check for vac leaks tomorrow and see if it runs better with the MAF unplugged. Car ran better tonight but kinda hunts at idle.

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    On cold startup, the O2 senders do absolutely nothing. The engine runs in open loop and fueling is controlled off the tables. I think the coolant has to hit somewhere between 120 and 140 degrees before the PCM switches over to closed loop. At that point, the PCM accepts feedback from the Bank 1, Sensor 1 and Bank 2, Sensor 1 oxygen sensors to adjust fueling. However, if something is amiss and the engine is going into closed loop fueling immediately upon startup, then there might be an impact on how it runs. The sendors are all electrically heated to bring them up to operating temperature sooner, but they do have a time lag.

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    Quote Originally Posted by pajeff02 View Post
    On cold startup, the O2 senders do absolutely nothing. The engine runs in open loop and fueling is controlled off the tables. I think the coolant has to hit somewhere between 120 and 140 degrees before the PCM switches over to closed loop. At that point, the PCM accepts feedback from the Bank 1, Sensor 1 and Bank 2, Sensor 1 oxygen sensors to adjust fueling. However, if something is amiss and the engine is going into closed loop fueling immediately upon startup, then there might be an impact on how it runs. The sendors are all electrically heated to bring them up to operating temperature sooner, but they do have a time lag.
    Are the sensor #1's the front sensors?

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    Spaz is My Mentor SMWS6TA's Avatar
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    yes

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    Quote Originally Posted by SMWS6TA View Post
    yes
    Hmmm, I gots no codes on the rear sensors so the PO must have done something with them then, either deleted them out or added eliminators I guess.

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    Spaz is My Mentor SMWS6TA's Avatar
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    disconnect the MAF see if it runs better.

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    Ok, got home, read codes, same codes I had cleared. Checked for vac leaks and did not find any. PVC system looks in pretty good shape except for the fact my PCV valve appears to be in the line by the front of the passenger side valve cover, I thought it was supposed to be on the back of the passenger side valve cover? Ran the car with MAF wires disconnected, ran the same. Found my 20A Engine sensor fuse blown. Looks like O2 sensor wires on the headers to me. Will get new fuses tomorrow to test and jack it up and check the O2 sensor wires.
    Question what's this vac line laying on top of the coil in the picture? It goes to the solenoid in the picture and does not appear to be pulling any vacuum. Something EGR/Air pump related?
    Attached Images Attached Images

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    Smiles for 9.5 Years cammed goat's Avatar
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    Is that pic facing the firewall? If so, I believe that connects to a nipple on the back of the intake manifold. Might go from the purge solenoid to the back of the manifold.

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    Yep, facing the firewall.

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    You've Seen The Butcher GoldenFlame's Avatar
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    cammed goat is right. That is a vacuum line that connects to the back of your intake manifold. Should point towards the passenger side under the MAP sensor. I believe it controls the air vents (HVAC)

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    You've Seen The Butcher GoldenFlame's Avatar
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    Just reread that entire post, I don't know what the hell that is then lol

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    Searched around yesterday, can't find anything on the back of the intake.

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    Spaz is My Mentor SMWS6TA's Avatar
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    Here you go...



    Look just under the wire harness and you'll see a small tube extending out. That is where the vacuum tube is suppose to connect. The big one is for your brake booster vacuum and the wire harness is for the MAP sensor..

    It will be a bitch to feel around because you're doing it blindly.





    Post #15 is correct it does control the HVAC a/c vents.

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    Quote Originally Posted by eteller View Post
    Question what's this vac line laying on top of the coil in the picture? It goes to the solenoid in the picture and does not appear to be pulling any vacuum. Something EGR/Air pump related?

    Appears to be the vacuum source line for the secondary air system. If you can't trace it, just plug the thing to be safe.

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